This invention relates to a threaded closure and container package and in particular to sealing means between the container and closure.
In the packaging industry, plastic containers are produced in which the threaded neck opening is not accurately sized or is out-of-round so that the closure does not property and accurately seal on its complementary sealing surface on the container. Also the closure and container may be manufactured by different entities and the dimensional tolerances may vary greatly In addition to facilitate threading of the closure relative to the container, ample thread tolerances are used which result in axial and radial displacement sufficient to cause misalignment of sealing surfaces. All of these variables and dimensional tolerances make it difficult to insure a good seal.
In the case of child resistant closures in which a lock interferes with the unthreading operation of the closure relative to the container a certain amount of rotation is permitted between the fully closed position and the position at which the locks engage to prevent further opening movement. This is necessary to insure orientation of the closure to one side of the lock in the fully closed position. However with the wide variance in dimensional tolerances and dimensional stability of the mating parts, it often is possible to rotate a closure in an opening direction sufficiently to break the seal before the child resistant lock engages to prevent further rotation or opening movement. In other words, it is possible to have a condition in which a child can rotate a closure sufficiently to cause leakage without overcoming the child resistant feature. This of course is a condition which cannot be tolerated.